1. Field of the invention
The present invention relates to an impact absorption steering apparatus, and more particularly to an impact absorption steering apparatus, in which a groove or a protuberance is formed at a mounting bracket and a plate bracket, respectively, instead of a capsule and a tearing plate used as an impact absorption apparatus of a conventional steering column, and then the protuberance is forcibly inserted and fixed in the groove, so as to absorb load due to collision through relative movement between the groove and the protuberance when impact energy is exerted to the steering column, thereby reducing manufacturing cost and manufacturing processes.
2. Description of the Prior Art
In general, a steering column is an apparatus which encloses and supports a steering shaft transferring rotational force generated by a steering wheel operated by a driver to a rack-pinion mechanism, and is fixed to a chassis of a vehicle through a bracket, so as to fix a position of the steering shaft.
When a vehicle crashes against an object, the upper part of a driver's body hits against the steering wheel and gets injured. In order to prevent this, an impact absorption steering column, which has a collapse function allowing a steering column and a steering shaft to be contracted in its shaft direction, has been employed as a steering column. Particularly, when a collision accident occurs during the driving, the upper body of the driver bumps against the steering wheel due to inertia. Therefore, as the upper body of the driver bumps against the steering wheel, the steering column and the steering shaft, which are disposed at the upper part of the vehicle, are contracted so as to reduce the impact exerted on the driver.
However, the collision energy transferred to the steering wheel due to the collision between the steering wheel and the driver depends on a driver state and a vehicle state. For example, large collision energy is transferred when the vehicle has a high speed, while small collision energy is transferred when the vehicle has a low speed. Further, the amount of the collision energy applied to the steering wheel depends on several conditions such as the wearing of driver's seat belt, operation of an air bag, etc. A steering apparatus equipped with a tearing plate has been developed to cope with these conditions.
FIG. 1 is a side view illustrating a conventional impact absorption steering column of a vehicle. As shown in FIG. 1, the conventional impact absorption steering column 100 includes: a steering shaft 102 having an upper end connected with a steering wheel (now shown) and a lower end connected with the rack-pinion mechanism (not shown); an inner tube 100 surrounding the steering shaft 102, an outer tube 120 surrounding the inner tube 10; a mounting bracket 130 which supports an outer circumferential surface of the outer tube 120 and is assembled with a chassis 104 of a vehicular through a capsule 140; a tearing plate 170 which has one end fixed in the capsule 140 by a fixing means and the other end fixed in the mounting bracket 130 by a fixing member 150; and a plate bracket 180 which encloses the outer tube 120 and has one side opened and the other side assembled with the mounting bracket 130.
When the upper part of driver's body collides with the steering wheel due to a frontal crashing of a vehicle, the steering column 100 is contracted in the direction (i.e. a collision energy transfer direction or a collapse direction) in which the impact has been applied to the steering wheel. Then, the mounting bracket 130 moves together with the exterior tube 120 in the collapse direction from the capsule 140 fixed on the chassis.
That is, when the collision occurs, the mounting bracket 130 is released from the capsule 140, and is easily released from the chassis 104, and then moves in the collapse direction (i.e. in the collision energy transfer direction), which the steering column 100 is contracted.
Also, in a case where the steering column 100 is contracted so as to allow the mounting bracket 130 and the capsule 140 to perform each relative movement so that the mounting bracket 130 moves downward, the tearing plate 170 receives forces, of which directions are opposite to each other, from the capsule 140 and the mounting bracket 130, respectively, so that the fixing member 160 included in the mounting bracket 130 changes the shape of the tearing plate 170, thereby absorbing impact energy.
Such a conventional impact absorption steering column employs a capsule and a tearing plate so as to absorb impact exerted when it collapses. Therefore, manufacturing cost is higher, and manufacturing processes also increase so that time required for manufacturing it is longer.